2022 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2022

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Algorytm mrówkowy do zarządzania zasobami sprzętowymi chmury obliczeniowej w przypadku różnych kategorii usług
- Henryk Krawczyk
- Piotr Orzechowski
2022
Zarządzanie chmurą obliczeniową odbywa się na dwóch poziomach: zarządzanie żądaniami klientów chmury oraz zarządzanie jej infrastrukturą, na której te usługi są realizowane. Analizując standardy dotyczące zarządzania usługami, w niniejszym rozdziale skoncentrowano się na drugim poziomie zarządzania, którego głównym celem jest efektywne wykonanie wskazanej usługi (lub usług) na dostępnych zasobach sprzętowych, tak by spełnione zostały przyjęte kryteria optymalizacyjne. Dotyczy to przede wszystkim algorytmów przydziału (alokacji) niezbędnych zasobów dla każdej z usług oczekujących na wykonanie, przy uwzględnieniu wymagań wynikających z zawartych umów pomiędzy użytkownikiem a dostawcą takich usług (SLA). Zaproponowano algorytm mrówkowy, który jest akceptowalny dla różnych kategorii zgłaszanych przez użytkowników żądań. Jego działanie zilustrowano na trzech konkretnych przykładach wykonywanych aplikacji. Dalsze eksperymentalne badania jakości proponowanego algorytmu są przewidywane po jego implementacji w systemie zarządzania lokalnej chmury TASKcloud.
AMO model for neuro-inclusive remote workplace
- Joanna Szulc
2022 Full text Personnel Review
Purpose The aim of this article is to extend current debates on organizational equality, diversity and inclusion to a consideration of neurodivergence in the remote workplace context. Design/methodology/approach Drawing on the ability, motivation, and opportunity (AMO) model and an emerging strength-based approach to neurodiversity, this conceptual paper integrates research on neurodiversity at work and remote working to provide a novel AMO model for a neuro-inclusive remote workplace. Findings Through a theoretically informed discussion of barriers to effective remote work from the perspective of neurominorities, the AMO model for the neuro-inclusive remote workplace is offered to assist organizations in creating an inclusive remote work environment where both neurominorities and neurotypicals can equally contribute to organizational success. Specific examples of how certain barriers to effective remote work can be mitigated are outlined and explained. Practical implications The conceptual model presented in this paper can assist HR practitioners in developing a comprehensive approach to skill, motivation, and opportunity-enhancing practices that are tailored to the unique needs of neurominorities in a specific context of remote work to generate mutual gains. Originality/value The model of interactions between individual and system factors offered enables a better theoretical understanding of the conditions under which high performance of neurodivergent individuals could be achieved with an associated positive impact on their well-being. The paper contributes to recent calls for more equitable and empathetic approaches to investing in employees with different cognitive profiles and does so in the underexplored context of remote work.
An Adaptive Network Model Simulating the Effects of Different Culture Types and Leader Qualities on Mistake Handling and Organisational Learning
- Natalie Samhran
- Jan Treur
- Wioleta Kucharska
- Anna Monika Wiewiora
2022
This paper investigates computationally the following research hypotheses: (1) Higher flexibility and discretion in organizational culture results in better mistake management and thus better organizational learning, (2) Effective organizational learning requires a transformational leader to have both high social and formal status and consistency, and (3) Company culture and leader's behavior must align for the best learning effects. Computational simulations of the introduced adaptive network were analyzed in different contexts varying in organization culture and leader characteristics. Statistical analysis results proved to be significant and supported the research hypotheses. Ultimately, this paper provides insight into how organizations that foster a mistake-tolerant attitude in alignment with the leader, can result in significantly better organizational learning on a team and individual level.
An analysis of observability and detectability for different sets of measured outputs - CSTR case study
- Mateusz Czyżniewski
- Rafał Łangowski
2022
A problem of proving the observability/detectability at a given measured output for non-linear biochemical systems has been addressed in this paper. A theory of indistinguishable state trajectories has been used to prove the properties of the observability or detectability of this system. It is related to taking system dynamics into consideration depending on initial conditions and the impact of inputs taking into account a given measured output. An analysis of the observability/ detectability has been performed for five cases where the various sets of measured outputs have been considered. The research results obtained are crucial for system state estimation that involves the synthesis of state observer. The proposed method may be successfully applied to the complex biochemical non-linear systems modelled as a continuous stirred tank reactor. Finally, the results obtained demonstrate the high effectiveness of the devised approach.
An Analysis of Sustainability Reporting Practices of the Global Airline Industry
- Eljas Johansson
2022 Full text
Sustainability reporting (SR) has become a standard practice for many organisations worldwide. The purpose of this paper is to explore and develop our understanding of the global airline industry’s SR practices. Content analysis was employed to map which reporting frameworks the global commercial airline industry has recently used to report their non-financial impacts. Additionally, comparisons were made in the application of SR between geographical regions. The results indicate that two-thirds of the global airline companies had not published sustainability reports online (reporting period 2019). The Global Reporting Initiative (GRI) was the most widely used reporting instrument from the five major non-financial reporting organisations’ frameworks. Also, over two-thirds of the reports had used the Sustainable Development Goals (SDGs) as a reference framework or referenced SDGs in other ways. This paper provides one of the broadest overviews of global airline SR practices. It is expected that the results will be of interest to practitioners and scholars in aviation SR.
An analytical four-layer horizontal electric current dipole model for analysing underwater electric potential in shallow seawater
- Mirosław Wołoszyn
- Krystian Buszman
- Tomasz Rutkowski
- Jarosław Tarnawski
- Javier Francisco Rodrigo Saura
2022 Full text Scientific Reports
The paper presents a new analytical four‑layer (air–water–bottom–non‑conductive layer) horizontal electric dipole model which allows an accurate approximation of ship’s Underwater Electric Potential (UEP) from a sufficient depth in shallow coastal marine waters. The numerical methods, usually Finite Element Method (FEM) or Boundary Elements Method (BEM), are typically used to estimate the electric field and the distribution of static electric components of UEP around the ship. These methods enable analyses with high accuracy but, compared to other point‑electrode methods and the proposed analytical model, they are relatively complex and need high computational time. The developed analytical model proposed in this paper allows real‑time calculations without significant loss of accuracy of the UEP estimations. In the model, the problem of boundary values at the borders of individual layers is solved using the reflection/image method and applying the idea of continuity of electric potential at a given boundary between two adjacent layers. Its accuracy is verified based on the synthetic data provided by specialised software packages making use of FEM and BEM numerical methods. A dimensionless quantitative analysis of the relationships between basic parameters of the proposed four‑layer analytical model and their impact on the accuracy of representation of individual electric field strength components is also delivered. The relationships between water and bottom conductivity and between water depth and bottom thickness are investigated and described. The obtained results show that the developed model allows detailed and reliable analysis of the electric field, especially in shallow coastal waters.
An automatic selection of optimal recurrent neural network architecture for processes dynamics modelling purposes
- Krzysztof Laddach
- Rafał Łangowski
- Tomasz Rutkowski
- Bartosz Puchalski
2022 Full text APPLIED SOFT COMPUTING
A problem related to the development of algorithms designed to find the structure of artificial neural network used for behavioural (black-box) modelling of selected dynamic processes has been addressed in this paper. The research has included four original proposals of algorithms dedicated to neural network architecture search. Algorithms have been based on well-known optimisation techniques such as evolutionary algorithms and gradient descent methods. In the presented research an artificial neural network of recurrent type has been used, whose architecture has been selected in an optimised way based on the above-mentioned algorithms. The optimality has been understood as achieving a trade-off between the size of the neural network and its accuracy in capturing the response of the mathematical model under which it has been learnt. During the optimisation, original specialised evolutionary operators have been proposed. The research involved an extended validation study based on data generated from a mathematical model of the fast processes occurring in a pressurised water nuclear reactor.
An Empirical Study on the Impact of Gender on Mobile Applications Usability
- Paweł Weichbroth
2022 Full text IEEE Access
In the area of broadband wireless Internet, mobile applications have already replaced their desktop equivalents and are recognized as valuable tools for any size of businesses and for private use. With the emergence of millions of apps, the quality of their interaction with the user remains an open question for software vendors. While female and male requirements and preferences are not always similar, to the best of our knowledge, few studies have examined the impact of gender on mobile applications usability. Therefore, the goal of this study is to assess their usability from the perspective of female and male users, and to evaluate the differences between them. In our study, based on an experimental setup with a group of 40 users (16 females and 24 males), with regard to three usability attributes, namely efficiency, effectiveness and satisfaction, both qualitative and quantitative data were collected, respectively via pre- and post-testing questionnaires and during application testing sessions, combined with the think aloud protocol. To analyze the collected data, descriptive statistics were extracted from the video data and used to calculate the inferential statistics. With a significance level (alpha) of 5%, our findings show that between the groups of females and males, there were no statistically significant differences in the performance accuracy, average completion time, and perceived satisfaction, since all p values are greater than the assumed alpha. Hence, one can conclude that no effect of gender was observed with regard to the usability of the Gmail application. Overall, the empirical results contribute to the ongoing research on mobile application usability by providing evidence-based insights that we believe may be valuable for both theory and practice.
An Extended Control of the Input Angle for Matrix Converters Connected with the Non-Unity Power Factor Loads.
- Paweł Szczepankowski
2022 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
This paper proposes a novel PWM modulation algorithm for Multiphase Conventional Matrix Converters (MCMC), with 3 inputs and k outputs, using the transfer function of the load angle. The proposed approach extends the range of power angle control at the input during the operation with a maximum voltage transfer ratio. The proposed concept is based on the Direct Analytic Voltage PWM (DAV--PWM) modulation with an elliptical trajectory of reference load voltages. The proposal has been verified using the circuit simulation in PSIM software, symbolic analysis using Matlab, and finally through an experiment.
An Innovative Antenna Array with High Inter Element Isolation for Sub-6 GHz 5G MIMO Communication Systems
- Mohammad Alibakhshikenari
- Bal S. Virdee
- Harry Benetatos
- Esraa Mousra Ali
- Mohammad Soruri
- Mariana Dalarsson
- Mohammad Naser-moghadasi
- Chan Hwang See
- Anna Pietrenko-Dąbrowska
- Mateusz Kozieł
- Stanisław Szczepański
- Ernesto Limiti
2022 Full text Scientific Reports
A novel technique is shown to improve the isolation between radiators in antenna arrays. The proposed technique suppresses the surface-wave propagation and reduces substrate loss thereby enhancing the overall performance of the array. This is achieved without affecting the antenna’s footprint. The proposed approach is demonstrated on a four-element array for 5G MIMO applications. Each radiating element in the array is constituted from a 3×3 matrix of interconnected resonant elements. The technique involves (i) incorporating matching stubs within the resonant elements, (ii) framing each of the four-radiating elements inside a dot-wall, and (iii) defecting the ground plane with dielectric slots that are aligned under the dot-walls. Results show that with the proposed approach the impedance bandwidth of the array is increased by 58.82% and the improvement in the average isolation between antennas #1&2, #1&3, #1&4 are 8 dB, 14 dB, 16 dB, and 13 dB, respectively. Moreover, improvement in the antenna gain is 4.2% and the total radiation efficiency is 23.53%. These results confirm the efficacy of the technique. The agreement between the simulated and measured results is excellent. Furthermore, the manufacture of the antenna array using the proposed approach is relatively straightforward and cost effective.
An innovative method of measuring the extension of the piston rod in hydraulic cylinders, especially large ones used in the shipbuilding and offshore industry
- Czesław Dymarski
- Paweł Dymarski
- Piotr Grymajło
2022 Full text Polish Maritime Research
The article presents the results of selected works related to the wider subject of research conducted at the Faculty of Mechanical Engineering and Shipbuilding at the Gdańsk University of Technology, regarding designing various on board devices with hydraulic drive for ships and other offshore facilities. One of the commonly used these mechanisms are hydraulic actuators with the measurement of the piston rod extension. The issue of precise measurement of the piston rod extension is extremely important in modern technologies of construction, assembly and precise displacement and positioning of large and heavy, both land and ocean engineering objects or structural elements with the use of several large hydraulic cylinders working in parallel. The article presents a one of two new patented P.425099 – A device for measuring the extension of a hydraulic cylinder piston rod. [1].
An investigation on residual stress and fatigue life assessment of T-shape welded joints
- Farzaneh Samadi
- Jeetendra Mourya
- Greg Wheatley
- Mohammed Nizam Khan
- Reza Masoudi Nejad
- Ricardo Branco
- Wojciech Macek
2022 Full text ENGINEERING FAILURE ANALYSIS
This paper aims to quantitatively evaluate the residual stress and fatigue life of T-type welded joints with a multi-pass weld in different direction. The main research objectives of the experimental test were to test the residual stress by changing direction along with multiple wielding passes and determine the fatigue life of the welded joints. The result shows that compressive residual stress increases in the sample gradually from single-pass weld to double and triple-pass weld. Moreover, the fatigue life of the specimen also gradually improves with an increasing number of welding passes. Performing multi-pass welding in different directions affects the material’s residual stress and fatigue life, which is an essential factor to consider for assuring the strength of the welded joint.
An isogeometric finite element formulation for boundary and shell viscoelasticity based on a multiplicative surface deformation split
- Karsten Paul
- Roger Sauer
2022 Full text INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
This work presents a numerical formulation to model isotropic viscoelastic material behavior for membranes and thin shells. The surface and the shell theory are formulated within a curvilinear coordinate system,which allows the representation of general surfaces and deformations. The kinematics follow from Kirchhoff–Love theory and the discretization makes use of isogeometric shape functions. A multiplicative split of the surface deformation gradient is employed, such that an intermediate surface configuration is introduced. The surface metric and curvature of this intermediate configuration follow from the solution of nonlinear evolution laws—ordinary differential equations—that stem from a generalized viscoelastic solid model. The evolution laws are integrated numerically with the implicit Euler scheme and linearized within the Newton–Raphson scheme of the nonlinear finite element framework. The implementation of membrane and bending viscosity is verified with the help of analytical solutions and shows ideal convergence behavior. The chosen numerical examples capture large deformations and typical viscoelasticity behavior, such as creep, relaxation, and strain rate dependence. It is also shown that the proposed formulation can be straightforwardly applied to model boundary viscoelasticity of 3D bodies.
An isogeometric finite element formulation for frictionless contact of Cosserat rods with unconstrained directors
- Myung-Jin Choi
- Sven Klinkel
- Roger Sauer
2022 Full text COMPUTATIONAL MECHANICS
This paper presents an isogeometric finite element formulation for nonlinear beams with impenetrability constraints, based on the kinematics of Cosserat rods with unconstrained directors. The beam cross-sectional deformation is represented by director vectors of an arbitrary order. For the frictionless lateral beam-to-beam contact, a surface-to-surface contact algorithm combined with an active set strategy and a penalty method is employed. The lateral boundary surface of the beam is parameterized by its axis and cross-sectional boundary curves with NURBS basis functions having at leastC2-continuity,which yields a continuous surface metric and curvature for the closest point projection. Three-dimensional constitutive laws of hyperelastic materials are considered. Several numerical examples verify the accuracy and efficiency of the proposed beam contact formulation in comparison to brick element solutions. The lateral contact pressure distribution of the beam formulation is in excellent agreement with the contact pressure of the brick element formulation while requiring much less degrees-of-freedom.
An MOR Algorithm Based on the Immittance Zero and Pole Eigenvectors for Fast FEM Simulations of Two-Port Microwave Structures
- Grzegorz Fotyga
- Damian Szypulski
- Adam Lamęcki
- Piotr Sypek
- Michał Rewieński
- Valentin de la Rubia
- Michał Mrozowski
2022 Full text IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
The aim of this article is to present a novel model-order reduction (MOR) algorithm for fast finite-element frequency-domain simulations of microwave two-port structures. The projection basis used to construct the reduced-order model (ROM) comprises two sets: singular vectors and regular vectors. The first set is composed of the eigenvectors associated with the poles of the finite-element method (FEM) state-space system, while the second one is made up from the eigenvectors corresponding to the zeros of the diagonal elements of the matrix-valued immittance transfer function. Importantly, just one LU factorization of the FEM system is required to construct the projection basis during the reduction process, due to the application of a new formulation based on the Schur complement. The sets of eigenvectors that are used in the basis are independent of one another, which makes the new technique better suited for parallel computing compared with previously developed methods, which are sequential in nature. The reliability and accuracy of the proposed scheme are compared with that of the standard MOR technique, namely, the reduced-basis method (RBM), and verified through the analysis of three microwave structures: an eighth-order dual-mode waveguide filter, a dielectric resonator filter, and a folded waveguide filter.
An observability and detectability analysis for non-linear uncertain CSTR model of biochemical processes
- Mateusz Czyżniewski
- Rafał Łangowski
2022 Full text Scientific Reports
The problem of proving observability/detectability properties for selected non-linear uncertain model of biochemical processes has been addressed in this paper. In particular, the analysis of observability/detectability in the face of parametric and unstructured uncertainty in system dynamics transformed into unknown inputs, and unknown initial conditions has been performed. Various sets of system measured outputs were taken into account during the research. The considered biochemical processes were modelled as a continuous stirred tank reactor with the microbial growth reaction and microbial mortality with the aggregated substrate and biomass concentrations in aerobic phase. Classical tools based on differential geometry and the method of indistinguishable state trajectories (indistinguishable dynamics) were used to verify the properties of the system. The observability/detectability analysis was performed for nine cases covering a wide range of possible combinations of system measured outputs and unknown inputs. The obtained results of are crucial meaning for system state reconstruction (estimation), which involves the synthesis of state observers.
An optimal designed experiment for the alkaline hydrolysis of feather keratin
- Małgorzata Dąbrowska
- Agata Sommer
- Izabela Sinkiewicz
- Antoni Taraszkiewicz
- Hanna Staroszczyk
2022 Full text ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
Feathers, burdensome waste from the poultry industry, can be a cheap source of keratin, a protein with excellent physico- chemical, biological, and mechanical properties. Acid and alkaline hydrolyses are usually adopted for isolation of keratin from its natural resources. This study aimed at assessing the statistically significant effect of input variables in the alkaline hydrolysis of keratin from chicken feathers on the process yield and on the molecular weight of peptides obtained. The effect of the volume ratio of 1M NaOH to the feathers’ mass, the hydrolysis time, and the shaking speed of the reaction mixture on the process yield were analyzed. The use of statistical analysis at the design step of experiment allowed reducing the trial number from 27 to 9. Among the input variables analyzed, only the volume ratio of 1M NaOH to the feathers’ mass had a significant effect on the process yield, while none of them significantly affected the molecular weight of the peptides obtained. All hydrolysates were dominated by two peptides’ fractions, with molecular weights of ca. 130 and 250 kDa, and mixture of many peptides of weight close to 10 kDa and smaller. Alkaline hydrolysis of feather keratin yielded protein hydrolysates soluble over a wide pH range.
An optimal form of the finite element mass matrix in the analysis of longitudinal vibrations of rods
- Magdalena Palacz
- Marek Krawczuk
2022 Full text FINITE ELEMENTS IN ANALYSIS AND DESIGN
In this paper, an attempt is made to find the optimal form of the mass matrix of a rod finite element, which allows one to obtain the smallest errors in the longitudinal frequency determination of natural vibrations of any boundary conditions within the whole range of determined frequencies. It is assumed that the mass matrix can be treated as a linear combination of the consistent and diagonal matrices. Based on analytical considerations, the optimal values of certain weights for creating a linear combination of the mentioned matrices have been determined. As a result, a mass matrix has been obtained which allows the determination of natural frequencies with the smallest mean error within the possible spectrum of frequencies. It is also shown that the value of the weight coefficient changes depending on the number of natural frequencies within the spectrum one wants to determine.
AN OVERVIEW OF HEAT TRANSFER ENHANCEMENT BASED UPON NANOPARTICLES INFLUENCED BY INDUCED MAGNETIC FIELD WITH SLIP CONDITION VIA FINITE ELEMENT STRATEGY
- Muhammad Bilal Hafeez
- Marek Krawczuk
- Hasan Shahzad
2022 Full text Acta Mechanica et Automatica
The mathematical model of heat generation and dissipation during thermal energy transmission employing nanoparticles in a Newtonian medium is investigated. Dimensionless boundary layer equations with correlations for titanium dioxide, copper oxide, and aluminium oxide are solved by the finite element method. Parameters are varied to analyze their impact on the flow fields. Various numerical experiments are performed consecutively to explore the phenomenon of thermal performance of the combination fluid. A remarkable enhancement in thermal performance is noticed when solid structures are dispersed in the working fluid. The Biot number determines the convective nature of the boundary. When the Biot number is increased, the fluid temperature decreases significantly. Among copper oxide, aluminium oxide, and titanium oxide nanoparticles, copper oxide nanoparticles are found to be the most effective thermal enhancers.
An Overview of Treatment Approaches for Octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX) Explosive in Soil, Groundwater, and Wastewater
- Varsha Srivastava
- Grzegorz Boczkaj
- Ulla Lassi
2022 Full text International Journal of Environmental Research and Public Health
Octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX) is extensively exploited in the manufacturing of explosives; therefore, a significant level of HMX contamination can be encountered near explosive production plants. For instance, up to 12 ppm HMX concentrations have been observed in the wastewater effluent of a munitions manufacturing facility, while up to 45,000 mg/kg of HMX has been found in a soil sample taken from a location close to a high-explosive production site. Owing to their immense demand for a variety of applications, the large-scale production of explosives has culminated in severe environmental issues. Soil and water contaminated with HMX can pose a detrimental impact on flora and fauna and hence, remediation of HMX is paramount. There is a rising demand to establish a sustainable technology for HMX abatement. Physiochemical and bioremediation approaches have been employed to treat HMX in the soil, groundwater, and wastewater. It has been revealed that treatment methods such as photo-peroxidation and photo-Fenton oxidation can eliminate approximately 98% of HMX from wastewater. Fenton’s reagents were found to be very effective at mineralizing HMX. In the photocatalytic degradation of HMX, approximately 59% TOC removal was achieved by using a TiO2 photocatalyst, and a dextrose co-substrate was used in a bioremediation approach to accomplish 98.5% HMX degradation under anaerobic conditions. However, each technology has some pros and cons which need to be taken into consideration when choosing an HMX remediation approach. In this review, various physiochemical and bioremediation approaches are considered and the mechanism of HMX degradation is discussed. Further, the advantages and disadvantages of the technologies are also discussed along with the challenges of HMX treatment technologies, thus giving an overview of the HMX remediation strategies.